...
- http://hollywoodposterframes.com/ - pre-built frames,
- http://www.spotlightdisplays.com/ - Flip frames (not sure what that means),
- www.displays2go.ca - search for snap frames (also has lightbox models)
Links,
- Canadian in Port Perry for Linen Backing - http://www.backingtothefuture.com/services/
- Good Forum Discussions - http://www.allposterforum.com/index.php/board,59.0.html
...